ABSTRACT
Mirabegron is the first registered ß3-adrenoceptor agonist for treatment of overactive bladder as an alternative to antimuscarinics. Previously four liquid chromatography-tandem mass spectrometry assays were published to determine mirabegron and eight metabolites (M5, M8, M11-M16) in human plasma. In order to support paediatric development, the assays were further optimized to reduce the required blood volume and increase the sensitivity. The assays were miniaturized by using 96-well supported liquid extraction plates (mirabegron, M5, M16) or 96-well mixed-mode cation exchange solid phase extraction plates (M8, M11-M15) and a more sensitive MS-system was used. For the analytes, up to fivefold increase in assay sensitivity was achieved. The required blood sample volume was reduced from 10 to 2 mL for each timepoint. Validation demonstrated that the assays were accurate, precise and selective in the determination of mirabegron and metabolites. The assays were successfully applied to evaluate the pharmacokinetics of mirabegron in a paediatric population.
Subject(s)
Acetanilides/blood , Adrenergic beta-3 Receptor Agonists/blood , Thiazoles/blood , Acetanilides/metabolism , Adrenergic beta-3 Receptor Agonists/metabolism , Child , Chromatography, Liquid , Dose-Response Relationship, Drug , Female , Humans , Male , Reproducibility of Results , Sensitivity and Specificity , Solid Phase Extraction , Tandem Mass Spectrometry , Thiazoles/metabolismABSTRACT
The aim of this work was to assess the influence of preanalytical variables on the stability of two endogenous opioid peptides (Methionine-Enkephalin and Leucine-Enkephalin) in human plasma. For this purpose, first a sensitive LC-MS/MS analytical method was developed and validated for the simultaneous quantitative analysis of these two peptides. The methodology consisted of a simple protein precipitation step followed by UPLC separation and MRM quantitative analysis using a stable isotope labelled Methionine-Enkephalin as internal standard. The method with a limit of quantitation of 10â¯pg/mL showed good reproducibility with excellent accuracy and precision, and was linear up to 2000â¯pg/mL. An extensive evaluation of the pre-analytical stability of these peptides in human blood was carried out to ensure an adequate sample collection procedure to obtain reliable results in the analysis of clinical samples.
